Question 1

The following questions refer to the evolutionary tree in the figure below.
The horizontal axis of the cladogram depicted below is a timeline that extends from 100,000 years ago to the present; the vertical axis represents nothing in particular. The labeled branch points on the tree (V-Z)represent various common ancestors. Let's say that only since 50,000 years ago has there been enough variation between the lineages depicted here to separate them into distinct species, and only the tips of the lineages on this tree represent distinct species.

In Darwin's tree of life, each fork in the tree represents ________.
A) groups of living organisms
B) groups of extinct organisms
C) the most recent common ancestor of the subsequent branches
D) morphologic gaps in the fossil record

Accepted Answer

Each fork in Darwin's tree of life represents the most recent common ancestor of the subsequent branches. This means that the common ancestor of the branches leading to V and W is represented by the fork that connects V, W, and X, and the common ancestor of the branches leading to Y and Z is represented by the fork that connects Y, Z, and X. The tips of the branches represent the distinct species that have evolved since the common ancestors. In this specific cladogram, the horizontal axis also represents a timeline, with the present on the far right and 100,000 years ago on the far left.

Question 2

What are adaptations?
A) geologic changes over time
B) rocks containing fossils
C) inherited characteristics of organisms that enhance their survival
D) descent with modification from a common ancestor

Accepted Answer

Adaptations are inherited characteristics of organisms that enhance their survival in a particular environment or situation. Adaptations can include physical structures, physiological functions, and behaviors. They are the result of natural selection, which favors traits that increase an organism's chances of survival and reproduction.

Question 3

Which pair of scientists below would probably have agreed with the process that is depicted by this tree?
A) Cuvier and Lamarck
B) Darwin and Wallace
C) Aristotle and Lyell
D) Wallace and Linnaeus

Accepted Answer

The process depicted in the tree is evolution by natural selection, which was the theory proposed by Darwin and Wallace in the mid-19th century. Cuvier and Lamarck's ideas on evolution differed greatly from Darwin and Wallace's, as did Aristotle's and Lyell's. Wallace and Linnaeus were contemporaries, but Linnaeus did not propose a mechanism for evolution.

Question 4

When Cuvier considered the fossils found in the vicinity of Paris, he concluded that the extinction of species ________.
A) does not occur, but evolution does occur
B) and the evolution of species both occur
C) and the evolution of species do not occur
D) occurs, but that there is no evolution

Accepted Answer

Cuvier concluded that the fossils found in the vicinity of Paris indicated that species had become extinct, but that there was no evidence of evolution.

Question 5

The Linnaeus classification system grouped organisms by ________.
A) linear hierarchy of the scala naturae
B) increasingly more general categories
C) increasingly more complex categories
D) environmental location

Accepted Answer

The Linnaeus classification system used a hierarchical system of increasingly more general categories to group organisms.

Question 6

A farmer uses triazine herbicide to control pigweed in his field. For the first few years, the triazine works well and almost all the pigweed dies; but after several years, the farmer sees more and more pigweed. Which of these statements explains why the pigweed reappeared?
A) The herbicide company lost its triazine formula and started selling poor-quality triazine.
B) Natural selection caused the pigweed to mutate, creating a new triazine-resistant species.
C) Triazine-resistant pigweed has less-efficient photosynthesis metabolism.
D) Triazine-resistant weeds were more likely to survive and reproduce.

Accepted Answer

Over time, repeated exposure to triazine herbicide led to the selection of a population of pigweed that was resistant to the herbicide. These resistant individuals were able to survive and reproduce, passing on their resistance to their offspring. As a result, the population of pigweed in the field shifted towards the triazine-resistant phenotype, leading to a resurgence of the weed.

Question 7

The cow Bos primigenius (which is bred for meat and milk)has a smaller brain and larger eyes than closely related wild species of ungulates. These traits most likely arose by ________.
A) natural selection, because these traits evolved in the population over time
B) natural selection, because these traits were not consciously selected by humans
C) artificial selection, because changes in these traits co-occurred with human selection for high milk output and high muscle content
D) artificial selection, because these animals differ from their close relatives and common ancestor

Accepted Answer

The smaller brain and larger eyes in domestic cows are likely the result of artificial selection, as they co-occurred with human selection for high milk output and muscle content. Natural selection is less likely to be responsible, as these traits may not necessarily provide a selective advantage in a wild population. Furthermore, the fact that these traits differ from their close relatives and common ancestor strongly suggests a human influence through artificial selection.

Question 8

The following questions refer to the figure below, which shows an outcrop of sedimentary rock whose strata are labeled A-D.

If x indicates the location of fossils of two closely related species, then fossils of their most-recent common ancestor are most likely to occur in which stratum?
A) A
B) B
C) C
D) D

Accepted Answer

The answer of The following questions refer to the figure...

Question 9

If x indicates the fossils of two closely related species, neither of which is extinct, then their remains may be found in how many of these strata?
A) one stratum
B) two strata
C) three strata
D) four strata

Accepted Answer

If two closely related species coexist, they will likely have overlapping ranges in geologic time. This means their fossils would be found in two stratigraphic layers.

Question 10

Darwin and Wallace's theory of evolution by natural selection was revolutionary because it ________.
A) was the first theory to refute the ideas of special creation
B) proved that individuals acclimated to their environment over time
C) dismissed the idea that species are constant and emphasized the importance of variation and change in populations
D) was the first time a biologist had proposed that species changed through time

Accepted Answer

Darwin and Wallace's theory of evolution by natural selection was revolutionary because it dismissed the ancient idea that species are constant and emphasized the importance of variation and change in populations. It was not the first theory to refute the ideas of special creation, as earlier scientists like Lamarck had also proposed ideas that challenged this concept. Similarly, the theory did not prove that individuals acclimated to their environment over time, as natural selection acts on populations and the traits of individuals that are advantageous in their environment are more likely to be passed on to future generations. Additionally, while the theory was groundbreaking in proposing that species changed through time, it was not the first time a biologist had proposed this idea as earlier scientists like Buffon had also suggested that species could change.

Question 11

After the drought of 1977, researchers hypothesized that on the Galápagos Island Daphne Major, medium ground finches with large, deep beaks survived better than those with smaller beaks because they could more easily crack and eat the tough Tribulus cistoides fruits. A tourist company sets up reliable feeding stations with a variety of bird seeds (different types and sizes)so that tourists can get a better look at the finches. Which of these events is now most likely to occur to finch beaks on this island?
A) evolution of yet larger, deeper beaks over time, until all birds have relatively large, deep beaks
B) evolution of smaller, pointier beaks over time, until all birds have relatively small, pointy beaks
C) increased variation in beak size and shape over time
D) no change in beak size and shape over time

Accepted Answer

The feeding stations set up by the tourist company provide a reliable source of food for the finches, reducing the selection pressure for larger, deeper beaks to crack tough Tribulus cistoides fruits. As a result, there may be increased variation in beak size and shape over time as other factors, such as competition for different types of seeds, become more important in natural selection. Therefore, option C is the most likely scenario for finch beak evolution on the island.

Question 12

Fossils found in strata reveal that ________.
A) older strata carry fossils that differ greatly from living organisms
B) geologic changes occur quickly on Earth
C) unused body parts decrease in size
D) innate drive to complexity of life

Accepted Answer

Fossils found in older strata show that the organisms were very different from modern-day organisms, indicating that significant changes in species have occurred over time. This supports the theory of evolution, which suggests that species evolve over long periods of time through the process of natural selection.

Question 13

Which of the following statements best explains why modification or change in an organ or tissue during the lifetime of an individual is not inherited?
A) Characteristics acquired during an organism's life are generally not passed on through genes.
B) Spontaneous mutations can result in the appearance of new traits.
C) Only favorable adaptations have survival value.
D) Disuse of an organ may lead to its eventual disappearance.

Accepted Answer

The inheritance of traits from one generation to the next is determined by genes, and traits acquired during an individual's lifetime are not incorporated into their genetic material and thus cannot be passed on to their offspring. This is known as the principle of inheritance of acquired characteristics, which has been discredited by modern genetics.

Question 14

Which one of the following statements best defines artificial selection?
A) Process that occurs when individuals inherit traits that enable them to survive and reproduce
B) Process where humans decide which plants and/or animals will not breed
C) Process of human directed breeding aimed to produce selective traits in selected species
D) Process that favors beneficial mutations

Accepted Answer

Artificial selection is the process of selective breeding by humans that aims to produce specific desired traits in the species. In this process, humans decide which plants or animals will breed based on the desired outcomes they want to achieve. This is different from natural selection, where traits are selected based on the survival and reproductive advantage they confer to individuals in the wild. Therefore, option C is the best definition of artificial selection.

Question 15

Which statement illustrates the connection between natural selection and overreproduction of a population?
A) Populations vary in their inherited traits.
B) Species produce more offspring than can survive in the environment.
C) Individuals with inherited traits that promote survival tend to have more surviving offspring.
D) Individuals with traits that do not enhance survival cannot reproduce.

Accepted Answer

The answer of Which statement illustrates the connection between natural...

Question 16

Starting from the wild mustard Brassica oleracea, breeders have created the strains known as Brussels sprouts, broccoli, kale, and cabbage. Therefore, which of the following statements is correct?
A) In this wild mustard, there is enough heritable variation to permit these different varieties.
B) Heritable variation is low in wild mustard-otherwise this wild strain would have different characteristics.
C) Natural selection is rare in wild populations of wild mustard.
D) In wild mustard, most of the variation is due to differences in soil or other aspects of the environment.

Accepted Answer

The statement implies that there is enough heritable variation in the wild mustard Brassica oleracea to allow for the development of varieties like Brussels sprouts, broccoli, kale, and cabbage. Therefore, option A is correct. Option B is incorrect as the statement suggests that there is enough heritable variation in the wild mustard. Option C is not mentioned in the given statement. Option D contradicts the statement, which implies that the variation is heritable, not solely due to differences in the environment.

Question 17

For which one of the following observations were both Lamarck's hypothesis and Darwin's hypothesis in complete agreement?
A) Use and disuse of organs determines their size in progeny.
B) Gradual evolutionary change explains why organisms are well-suited to their environments.
C) Acquired characteristics are inherited.
D) More complex species are descended from less complex species.

Accepted Answer

Both Lamarck's hypothesis and Darwin's hypothesis agree on the concept of gradual evolutionary change, which explains why organisms are well-suited to their environments. However, Lamarck's hypothesis also included the concept of acquired characteristics being inherited, which Darwin's hypothesis did not support.

Question 18

Prior to the work of Lyell and Darwin, the prevailing belief was that Earth is ________.
A) a few thousand years old, and populations are unchanging
B) a few thousand years old, and populations gradually change
C) millions of years old, and populations rapidly change
D) millions of years old, and populations are unchanging

Accepted Answer

Prior to the work of Lyell and Darwin, the prevailing belief was that Earth is only a few thousand years old, and populations are unchanging. This belief was based on religious and cultural traditions, rather than scientific evidence. It was not until the 19th century that geologists and biologists began to develop a more accurate understanding of the Earth's age and the processes that drive evolutionary change.

Question 19

Which of these conditions are always true of populations evolving due to natural selection?
Condition 1: The population must vary in traits that are heritable.
Condition 2: Some heritable traits must increase reproductive success.
Condition 3: Individuals pass on most traits that they acquire during their lifetime.
A) Condition 1 only
B) Condition 2 only
C) Conditions 1 and 2
D) Conditions 2 and 3

Accepted Answer

Condition 1 is necessary for there to be variation for natural selection to act upon. Condition 2 is necessary for certain heritable traits to be passed on at higher rates due to their increased reproductive success, leading to evolution. Condition 3 is not always true, as most acquired traits are not heritable and therefore cannot be passed on to offspring.

Question 20

The following question is based on information from Frank M. Frey, "Opposing Natural Selection from Herbivores and Pathogens May Maintain Floral-Color Variation in Claytonia virginica (Portulacaceae)," Evolution 58(11), 2004: 2426-37.
Claytonia virginica is a woodland spring herb with flowers that vary from white, to pale pink, to bright pink. Slugs prefer to eat pink-flowering over white-flowering plants (due to chemical differences between the two), and plants experiencing severe herbivory are more likely to die. The bees that pollinate this plant also prefer pink to white flowers, so that Claytonia with pink flowers have greater relative fruit set than Claytonia with white flowers. A researcher observes that the percentage of different flower colors remains stable in the study population from year to year. Given no other information, if the researcher removes all slugs from the study population, what do you expect to happen to the distribution of flower colors in the population over time?
A) The percentage of pink flowers should increase over time.
B) The percentage of white flowers should increase over time.
C) The distribution of flower colors should not change.
D) The distribution of flower colors should randomly fluctuate over time.

Accepted Answer

The answer of The following question is based on information...

Quiz 22: Descent with Modification: A Darwinian View of Life

What are adaptations?

Which pair of scientists below would probably have agreed with the process that is depicted by this tree?

When Cuvier considered the fossils found in the vicinity of Paris, he concluded that the extinction of species ________.

The Linnaeus classification system grouped organisms by ________.

A farmer uses triazine herbicide to control pigweed in his field. For the first few years, the triazine works well and almost all the pigweed dies; but after several years, the farmer sees more and more pigweed. Which of these statements explains why the pigweed reappeared?

The cow Bos primigenius (which is bred for meat and milk) has a smaller brain and larger eyes than closely related wild species of ungulates. These traits most likely arose by ________.

The following questions refer to the figure below, which shows an outcrop of sedimentary rock whose strata are labeled A-D. If x indicates the location of fossils of two closely related species, then fossils of their most-recent common ancestor are most likely to occur in which stratum?

If x indicates the fossils of two closely related species, neither of which is extinct, then their remains may be found in how many of these strata?

Darwin and Wallace's theory of evolution by natural selection was revolutionary because it ________.

Fossils found in strata reveal that ________.

Which of the following statements best explains why modification or change in an organ or tissue during the lifetime of an individual is not inherited?

Which one of the following statements best defines artificial selection?

Which statement illustrates the connection between natural selection and overreproduction of a population?

Starting from the wild mustard Brassica oleracea, breeders have created the strains known as Brussels sprouts, broccoli, kale, and cabbage. Therefore, which of the following statements is correct?

For which one of the following observations were both Lamarck's hypothesis and Darwin's hypothesis in complete agreement?

Prior to the work of Lyell and Darwin, the prevailing belief was that Earth is ________.